@@ -64,6 +64,7 @@ struct nullb_device {
unsigned int home_node; /* home node for the device */
unsigned int queue_mode; /* block interface */
unsigned int blocksize; /* block size */
+ unsigned int max_sectors; /* Max sectors per command */
unsigned int irqmode; /* IRQ completion handler */
unsigned int hw_queue_depth; /* queue depth */
unsigned int index; /* index of the disk, only valid with a disk */
@@ -152,6 +152,10 @@ static int g_bs = 512;
module_param_named(bs, g_bs, int, 0444);
MODULE_PARM_DESC(bs, "Block size (in bytes)");
+static int g_max_sectors;
+module_param_named(max_sectors, g_max_sectors, int, 0444);
+MODULE_PARM_DESC(max_sectors, "Maximum size of a command (in 512B sectors)");
+
static unsigned int nr_devices = 1;
module_param(nr_devices, uint, 0444);
MODULE_PARM_DESC(nr_devices, "Number of devices to register");
@@ -346,6 +350,7 @@ NULLB_DEVICE_ATTR(submit_queues, uint, nullb_apply_submit_queues);
NULLB_DEVICE_ATTR(home_node, uint, NULL);
NULLB_DEVICE_ATTR(queue_mode, uint, NULL);
NULLB_DEVICE_ATTR(blocksize, uint, NULL);
+NULLB_DEVICE_ATTR(max_sectors, uint, NULL);
NULLB_DEVICE_ATTR(irqmode, uint, NULL);
NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL);
NULLB_DEVICE_ATTR(index, uint, NULL);
@@ -463,6 +468,7 @@ static struct configfs_attribute *nullb_device_attrs[] = {
&nullb_device_attr_home_node,
&nullb_device_attr_queue_mode,
&nullb_device_attr_blocksize,
+ &nullb_device_attr_max_sectors,
&nullb_device_attr_irqmode,
&nullb_device_attr_hw_queue_depth,
&nullb_device_attr_index,
@@ -533,7 +539,7 @@ nullb_group_drop_item(struct config_group *group, struct config_item *item)
static ssize_t memb_group_features_show(struct config_item *item, char *page)
{
return snprintf(page, PAGE_SIZE,
- "memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size,zone_capacity,zone_nr_conv,zone_max_open,zone_max_active\n");
+ "memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size,zone_capacity,zone_nr_conv,zone_max_open,zone_max_active,blocksize,max_sectors\n");
}
CONFIGFS_ATTR_RO(memb_group_, features);
@@ -588,6 +594,7 @@ static struct nullb_device *null_alloc_dev(void)
dev->home_node = g_home_node;
dev->queue_mode = g_queue_mode;
dev->blocksize = g_bs;
+ dev->max_sectors = g_max_sectors;
dev->irqmode = g_irqmode;
dev->hw_queue_depth = g_hw_queue_depth;
dev->blocking = g_blocking;
@@ -1867,9 +1874,13 @@ static int null_add_dev(struct nullb_device *dev)
blk_queue_logical_block_size(nullb->q, dev->blocksize);
blk_queue_physical_block_size(nullb->q, dev->blocksize);
- blk_queue_max_hw_sectors(nullb->q,
- round_down(queue_max_hw_sectors(nullb->q),
- dev->blocksize >> SECTOR_SHIFT));
+ if (!dev->max_sectors)
+ dev->max_sectors = queue_max_hw_sectors(nullb->q);
+ dev->max_sectors = min_t(unsigned int, dev->max_sectors,
+ BLK_DEF_MAX_SECTORS);
+ dev->max_sectors = round_down(dev->max_sectors,
+ dev->blocksize >> SECTOR_SHIFT);
+ blk_queue_max_hw_sectors(nullb->q, dev->max_sectors);
null_config_discard(nullb);
@@ -1913,6 +1924,12 @@ static int __init null_init(void)
g_bs = PAGE_SIZE;
}
+ if (g_max_sectors > BLK_DEF_MAX_SECTORS) {
+ pr_warn("invalid max sectors\n");
+ pr_warn("defaults max sectors to %u\n", BLK_DEF_MAX_SECTORS);
+ g_max_sectors = BLK_DEF_MAX_SECTORS;
+ }
+
if (g_home_node != NUMA_NO_NODE && g_home_node >= nr_online_nodes) {
pr_err("invalid home_node value\n");
g_home_node = NUMA_NO_NODE;
Add the module option and configfs attribute max_sectors to allow configuring the maximum size of a command issued to a null_blk device. This allows exercising the block layer BIO splitting with different limits than the default BLK_SAFE_MAX_SECTORS. This is also useful for testing the zone append write path of file systems as the max_hw_sectors limit value is also used for the max_zone_append_sectors limit. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> --- drivers/block/null_blk.h | 1 + drivers/block/null_blk_main.c | 25 +++++++++++++++++++++---- 2 files changed, 22 insertions(+), 4 deletions(-)